Fracturing pump assembly

ABSTRACT

An improved fracturing pump is provided. The pump is reconfigurable on site. Internal components of the pump may be varied to meet the requirements of a specific operation. The reconfiguration gives the user the ability to increase or decrease the horsepower of the pump. A closed loop oil feed system provides constant and reliable lubrication even under heavy loads. The sealing system is enhanced to reduce leaks and thermal stresses. The pump also has an improved frame and chassis to reduce NVH and enhance reliability.

BACKGROUND OF THE INVENTION 1. Field of the Invention

This invention relates to pumps, and in particular, to an improvedfracturing pump assembly.

2. Description of the Prior Art

Drilling and production systems are often employed to access and extracthydrocarbons from subterranean formations. These systems may be locatedonshore or offshore depending on the location of a desired resource.Further, such systems generally include a wellhead assembly mounted on awell through which the resource is accessed or extracted. These wellheadassemblies may include a wide variety of components, such as variouscasings, valves, pumps, fluid conduits, and the like, that controldrilling or extraction operations.

Drilling and production operations, such as fracking, employ fluidsreferred to as drilling fluids to provide lubrication and cooling of thedrill bit, clear away cuttings, and maintain desired hydrostaticpressure during operations. Drilling fluids can include all types ofwater-based, oil-based, or synthetic-based drilling fluids. Pumps can beused to move large quantities of fluid. Operations come to a halt if thepumps fail, and thus, reliability under harsh conditions, using alltypes of abrasive fluids, is of utmost commercial interest. Also,portability of these pumps is an issue, so having a versatile pump whichcan meet the needs of virtually any situation would be desirable.

An improved fracturing pump is provided. The pump is reconfigurable onsite. Internal components of the pump may be varied to meet therequirements of a specific operation. The reconfiguration gives the userthe ability to increase or decrease the horsepower of the pump. A closedloop oil feed system provides constant and reliable lubrication evenunder heavy loads. The sealing system is enhanced to reduce leaks andthermal stresses. The pump also has an improved frame and chassis toreduce NVH and enhance reliability.

SUMMARY OF THE INVENTION

It is a major object of the invention to provide an improved fracturingpump assembly.

It is another object of the invention to provide a fracturing pumpassembly with interchangeable parts.

It is another object of the invention to provide a fracturing pumpassembly with a variable power output.

It is another object of the invention to provide a fracturing pumpassembly having an improved frame which utilizes partition support.

It is another object of the invention to provide a fracturing pumpassembly where the pump frame is integrated into the skid chassis.

It is another object of the invention to provide a fracturing pumpassembly with a closed loop lubricating system.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 generally depicts a wellsite system, in accordance with one ormore implementations described herein.

FIG. 2 shows a side cutaway view of a prior art pump.

FIG. 3 shows a perspective view of a first embodiment of a fracturingpump assembly.

FIG. 4 shows a perspective view of a frame and chassis configuration forthe pump of FIG. 3.

FIG. 5. shows a side cutaway view of a second embodiment of theinventive system using different gearing.

FIG. 6 shows a side cutaway view illustrating the pistons and connectingrods.

FIG. 7 shows a detail of the fluid handling end.

FIG. 8 shows a detail of the bearing assembly.

FIG. 9 shows a perspective view of a third embodiment of a fracturingpump assembly.

FIG. 10 shows a perspective view of a frame and chassis configurationfor the pump of FIG. 9.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Generally speaking, FIG. 1 illustrates a wellsite system in which theinventive fracturing pump can be employed. The wellsite system of FIG. 1may be onshore or offshore. In the wellsite system of FIG. 1, a borehole11 may be formed in subsurface formations by rotary drilling using anysuitable technique. A drill string 12 may be suspended within theborehole 11 and may have a bottom hole assembly 100 that includes adrill bit 105 at its lower end. A surface system of the wellsite systemof FIG. 1 may include a platform and derrick assembly 10 positioned overthe borehole 11, the platform and derrick assembly 10 including a rotarytable 16, kelly 17, hook 18 and rotary swivel 19. The drill string 12may be rotated by the rotary table 16, energized by any suitable means,which engages the kelly 17 at the upper end of the drill string 12. Thedrill string 12 may be suspended from the hook 18, attached to atraveling block (not shown), through the kelly 17 and the rotary swivel19, which permits rotation of the drill string 12 relative to the hook18. A top drive system could alternatively be used, which may be a topdrive system well known to those of ordinary skill in the art.

In the wellsite system of FIG. 1, the surface system may also includedrilling fluid 26 (also referred to as fracturing) stored in a pit/tank27 at the wellsite. A pump 29 supported on a skid 28 may deliver thedrilling fluid 26 to the interior of the drill string 12 via a port inthe swivel 19, causing the drilling fluid to flow downwardly through thedrill string 12 as indicated by the directional arrow 8. The drillingfluid 26 may exit the drill string 12 via ports in a drill bit 105, andcirculate upwardly through the annulus region between the outside of thedrill string 12 and the wall of the borehole 11, as indicated by thedirectional arrows 9. In this manner, the drilling fluid 26 lubricatesthe drill bit 105 and carries formation cuttings up to the surface, asthe drilling fluid 26 is returned to the pit/tank 27 for recirculation.The drilling fluid 26 also serves to maintain hydrostatic pressure andprevent well collapse. The drilling fluid 26 may also be used fortelemetry purposes. A bottom hole assembly 100 of the wellsite system ofFIG. 1 may include logging-while-drilling (LWD) modules 120 and 120Aand/or measuring-while-drilling (MWD) modules 130 and 130A, aroto-steerable system and motor 150, and the drill bit 105.

FIG. 2 shows a cutaway side view of a prior art fracturing pump,illustrating various components of the power assembly, the portion ofthe pump that converts rotational energy into reciprocating motion. Apump as shown in FIG. 2 could be used as pump 29 of FIG. 1, althoughmany other fracturing pumps, including those with designs describedbelow in accordance with certain embodiments of the present technique,could instead be used as pump 29. Pinion gears 52 along a pinion shaft48 drive a larger gear referred to as a bull gear 42 (e.g., a helicalgear or a herringbone gear), which rotates on a crankshaft 40. Pinionshaft 48 is turned by a motor (not shown). The crankshaft 40 turns tocause rotational motion of hubs 44 disposed on the crankshaft 40, eachhub 44 being connected to or integrated with a connecting rod 46. By wayof the connecting rods 46, the rotational motion of the crankshaft 40(and hub 44 connected thereto) is converted into reciprocating motion.The connecting rods 46 couple to a crosshead 54 (a crosshead block andcrosshead extension as shown may be referred to collectively as thecrosshead 54 herein). The crosshead 54 moves translationally constrainedby guide 57. Pony rods 60 connect the crosshead 54 to a piston 58. Inthe fluid end of the pump, each piston 58 reciprocates to movefracturing in and out of valves in the fluid end of the pump 29.

Referring now to FIGS. 3 and 4, it can be seen that the pump 100 has acrankshaft 102, which drives connecting rods 104, which ultimately causereciprocating action of the pistons 106 to create pumping action as inthe prior art model discussed above. The pump 100 has an enhancedstructural arrangement to increase pump reliability as can be seen mostparticularly in FIG. 4. It can be seen that the pump frame 105, has aseries of partitioning structural dividing walls 107 which serve toseparate the rods and pistons but is also configured to reduce NVH andincrease pump reliability. In a key aspect of the invention, NVHreduction greatly increases pump reliability by reducing stresses on thepump 100. The dual chassis skid arrangement 114 is enhanced by addingmultiple mounting points (for the pump 100 main body) for increasedrigidity and to reduce deflection under load. In a key aspect of theinvention, frame 105 and skid 114 are a single integrated structure,which greatly reduces noise, vibration, and harshness (NVH). Thereduction in NVH enhances power output significantly.

Referring now to FIGS. 5 and 6 a second embodiment of the pump 200 isshown. It can be seen that the pump 200 has a crankshaft 202, whichdrives connecting rods 204, which ultimately cause reciprocating actionof the pistons 206 to create pumping action as in the prior art model,and the previous embodiment discussed above. The pump 100 has the sameenhanced structural arrangement to increase pump reliability asdiscussed above, modified to accommodate the different geometry of thepump 200 versus pump 100.

A closed loop oil feed system 118, (218) common to both pumps 100, 200is part of an optimized lubrication system which reduces frictionbetween crosshead 116 (216) and crosshead guides 117 (217). Lowoperating lube oil temperatures and high mechanical efficiency increasereliability.

A robust sealing system is provided to improve leak and thermal stresseshandling during harsh high temperature fracturing operation in thefield. As previously stated, the interior components of the pump,including the plunger 140 (240), can be interchangeably replaced toincrease power output, a key aspect of the invention. In a preferredembodiment power generation for pumps 100, 200 range from 3000 HP to4150 HP by way of interchangeable components. Also, the pumps 100, 200allow variable high pressure output and high flow rate based on varianceof plunger size and stroke length. Specifically, an 8 inch strokecreates a horsepower of about 3000 HP, with 9, 10, and 11 inch strokescreating 3400 HP, 3755 HP, and 4150 HP, respectively. (See attached specsheet for additional details).

The enhanced fluid end assembly 123 is shown in FIG. 7. The cylindricalbearing assembly 127 is shown in FIG. 8. Both the fluid end assembly123, and bearing assembly 127 are common to both pumps 100, 200.

FIGS. 9 and 10 shows another alternative embodiment of the pump assembly300. The assembly 300 is a fracturing pump with gearbox drive horsepowercapability that can handle ranges between 3000 Hp to 5000 HP E/T usingdrive power electric motor or turbine engine E/T based on a gear boxratio between 6.963:1 to 10.50:1 with optimized weight and drive stroketo meet demand for high power, pressure and less equipment.

It can be seen that the pump 300 has a crankshaft 302, which drivesconnecting rods, which ultimately cause reciprocating action of thepistons to create pumping action as in the prior art model discussedabove. The pump 300 has an enhanced structural arrangement to increasepump reliability as can be seen most particularly in FIG. 10. It can beseen that the pump frame 305, has a series of partitioning structuraldividing walls 107 which serve to separate the rods and pistons but isalso configured to reduce NVH and increase pump reliability. In a keyaspect of the invention, NVH reduction greatly increases pumpreliability by reducing stresses on the pump 100. The dual chassis skidarrangement 314 is enhanced by adding multiple mounting points (for thepump 300 main body) for increased rigidity and to reduce deflectionunder load. In a key aspect of the invention, frame 305 and skid 314 area single integrated structure, which greatly reduces noise, vibration,and harshness (NVH). The reduction in NVH enhances power outputsignificantly.

The pump 300 uses the closed loop oil feed system 118, (218) common topumps 100, 200, which is part of an optimized lubrication system whichreduces friction between the crosshead and crosshead guides. Lowoperating lube oil temperatures and high mechanical efficiency increaselong term reliability.

It is to be understood that the present invention is not limited to thesole embodiment described above, but encompasses any and all embodimentswithin the scope of the following claims:

I claim:
 1. A fracturing pump assembly comprising: a frame having aplurality of bores formed therethrough; and a plurality of crossheadsdisposed in the plurality of bores, respectively, and adapted toreciprocate therein; a crankshaft for imparting motive power to aplunger, said plunger situated in the fluid handling end of the pump,whereby rotation of said crankshaft causes reciprocating movement ofsaid plunger which causes fluid to be expelled from the fluid handlingend of the pump.
 2. The pump assembly of claim 1 wherein said frame ismounted on a skid assembly, said skid assembly attached to said frame atmultiple mounting points to distribute vibration.
 3. The pump assemblyof claim 1 wherein a plurality of pistons are connected to respectiverods positioned within said frame, each of said rods coupled to saidcrankshaft for imparting rotating motive power thereto, said frameseparated internally by partitioning walls.
 4. The pump assembly ofclaim 1 wherein said pistons and rods are separated by said partitioningwalls.